Valve



S. l.,MacDUFF VALVE Filed Ilarch 14, 1946 Aug. l, 1950 INVENToR..5TH/14E), MCM/rf AWM/Vf),

Patented Aug.` l,

VALVE Stanley I. MacDui'f, South Bend, Ind., anlgnor to Bendix AviationCorporation, South Bend, Ind., a corporation of Delaware ApplicationMarch 14, 1946, Serial No. 654,416

` 9 Claims.

AThis invention relates generally to valves, and

more particularly to'that type of valve for use in a hydraulic system ona vehicle where the flow oi fluid from a single pump must be utilized tooperate a plurality of instruments, such as a steering gear and brakes,for example.

It is therefore an object of the invention to provide an operatoroperated valve which controls the flow of fluid from a single pump tosteering gear and brakes.

It is a further object of the invention to provide a valve for use in ahydraulic system on a. vehicle, operable to proportion the flow of fluidfrom a single pump, between the steering gear and brakes.

a, still further object of the invention resides in the provision of avalve in a hydraulic system to normally connect one of the devices inthe system to system ow, and another of the devices of the system toreservoir. A

Another important object `or the invention resides in the provision of avalve for a hydraulic system, which valve is constructed and arranged tonormally connect the steering gear to the pump and disconnect the brakestherefrom.

A further important object of the invention resides in the provision ofa valve for use with an openv fluid system having a steering geartherein and a closed Huid system having a booster unit therein, saidvalve so constructed and arranged that the flow of fluid to the steeringgear can be diverted to act on said booster unit to put fluid in theclosed system under pressure.

Another very important object of the invention resides in the provisionof an operator operated valve which produces position sense" and feel inaccordance with the braking edort of the operator.

The above and other objects and features of the invention V'will heapparent from the following description of the device taken inconnection with the accompanying diagrammatic drawing which forms a partof the specification and in which:

Figure l is a hydraulic system incorporating the device of theinvention;

Figure 2 is a sectional elevation showing the invention; and

Figure 3 is an enlarged view in detail of a portion of the piston valvewhich forms a partei the invention.

Referring to Figure 1 of the drawing, numeral II designates a uldreservoir which supplies fluid to a pump I2 which puts the iluid` underpressure to actuate brakes I4 and furnish fluid to a steerlng gear valveIB to aid ln steering a vehicle, not

(Cl. Gli-54.6)

shown. All o! the steering gear connections to the iluld pressure systemare not shown since they ,Y form no part of the present invention. Thebrakes I4 and the steering gear valve I8 are connected to thereservoir Iand pump I2 through an operator operatedvalve I8. To prevent thepressure on the iluid in line 20, which connects the pump I2 to valveIl, from rising above a predetermined value, a relief valve 22 isconnected in line 24 which connects the line 20 to a line 26. Line 28connects the valve I8 to the reservoir To protect the steering 4gearvalve from abnormally high pressures, a relief valve 28 is disposed in aline 30 which is arranged in the system to shunt the steering valve. AIline 30,

into which the relief valve 28 is inserted, is conin, which lands aregrooved at 54, 56 and 58 to receive seals 6B. Section M includes astepped bore G2 and 64 to accommodate apiston 66 having a large head 88at one end and a smaller head 'lll at the other end. The two sectionsare held together by bolts it which engage flanges 14 and i6 integrallyrelated to the sections d2 and 44 respectively at their ends. joinedtogether they provide a single bore with the piston located in one end.One end of bore 64 is closed at 18 and is provided with a boss 80drilled and threaded at Bt to receive a conduit for connecting thebrakes itto said one end of the bore. Section M is equipped with areservoir port 84 which opens into the large bore 6i. The piston 66 andbore 62 are together constituted to provide an axial extending annularchamber 85, which is in constant communication with said reservoir port.Section 42 includes a pumping port 88 which terminates in the cylinder4B between the lands 50 and 52, and a steering gear port or working port88 which terminates in cylinder 46 between the lands 48 and 5U.. The end1l is counterbored at 90 to receive one end of a spring 92, the free endof which engages the piston li to normally urge the same to the positionshown. A projection 94 is carried bythe large head $8 of the piston toforma stop which abuis When the sections are the flange 'i4 when thepiston is in its extreme leftward position. A ball valve 96 is disposedin a passage 88 which connects the ends of the piston 66. The ball valve86 is normally urged to close the passage 98 by a spring |00. Alongitudinally slotted valve pin |02 is arranged in the passage tounseat the ball valve 96 when the piston 66 is biased to its extremeleftward position as aforementioned. Unseating ball valve 96 permits thefree passage of fluid from the braking or Working port 82 to thereservoir port 84. 'Ihe piston 66 is bored longitudinally at |04,counterbored at |06 and bored radially at |08, to thereby furnish apassage or conduit connecting the chamber 85 to said one end of thepiston. A valve element having a valve seat ||2 is slidably disposed inthe counterbore |06. The valve element is centrally bored at ||3. Aretainer washer ||4 is located in the counterbore to arrest movement ofthe valve element I l0 to the left under the inuuence of a spring ||6.The reservoir port 84 opens into the bore 62 intermediate the large head68 and the small head l0 of the piston 66. Communication between theworking port 82 and the reservoir port 84, when the piston 66 is in theposition shown, is through passage 88, bore ||3 of the valve element,longitudinal bore |04 and radial bore |08 of the piston 66.

To control the flow of fluid between the pumping port 86 and the workingport 88, operator operated means is slidably disposed in section 42 andcomprises a sleeve |20 having radial openings |22 and |24 connecting theinterior of the sleeve to the exterior thereof. The lradial openings arelocated in the sleeve to by-pass the fluid around the land 50 and seal60 which would otherwise\ form a barrier to the passage of iluid betweenthe pumping port and working port 88. Pumping port 86 is located on oneside of the land 50 and the working port 88 is located on the other sideof the land vso that fluid passing from the port 86 to port 88 must passthrough the radial openings |22 and |24. Lands |26 and |28 are formedinteriorly of sleeve i20 to cooperate with a piston valve |30 to controlthe dow of iiuid to the port 88. 'The piston valve |30 which isrelatively movable with respect to sleeve i220, has a reduced portion|32 formed between shoulders |34 and |36 to provide a variable openingto port 88. To control the ilow of fluid from the pumping port 86 to thelarge end of piston piston valve |30 is slotted at 38 to register withland |28. The slots have inclined faces |39 to provide close regulationof the initial `flow of iiuid to the large head 68 of the piston. Oneend of the piston valve is provided'with a valve head 540 which engagesthe valve seat ||2 of the valve element I|0 to cut off communicationfrom the left end of piston 66 to the reservoir port 84. The end of thepiston valve on the opposite end from the valve head |40 slides in abearing |42 of the sleeve |20. That portion of the piston valve whichslides inthe bearing |42 is bored at |44 toreceive one end of arelatively light spring |46, the other end of which abuts a cap |48threadedly engaging one end of the sleeve to close the same and to forma bearing point on which the pedal ||9 rests. A longitudinal passage |49in the piston valve connects the two ends of the piston valveso that itwill be hydraulically balanced across its ends. I'he spring |46 urgesthe piston valve to a normal relative position in the sleeve where theshoulders |34 and |36 of the piston valve are equally spaced from theland |26 and the slots |38 are completely covered by land |28 to therebyestablish communication between the pumping port 86 and the working port88 and to cut oli communication between the pumping port and the largeend of the piston 88. A washer |50 is received by an annulus |52 of thepiston valve to provide a stop which locates the piston valve withinsleeve |20. .The sleeve |20 is limited in its movement to the left by anelement |56 secured to the end of the sleeve and so constituted toengage the land 52.

When valve I8 is mounted in the position shown in Figure 1, the weightof the piston valve, sleeve and pedal ||8 tend to seat the valve head|40 on the seat ||2 to normally close the passage H3. The arrangementbetween valve head and valve seat ||2 is such as to .act as a reliefvalve should the pressure acting on the large head 68 of piston 66become excessive. Should hydraulic power fail, sleeve |20 is moved tothe right until element |56 of the sleeve engages the large end of thepiston 66 to move the piston to the right to manually build upsuiiicient pressure behind piston 66 to operate the brakes.

The relationship between lands |26 and |28 to shoulder I 36 and slots|38, respectively, is such that slots |38 are slightly uncovered toadmit fluidiunder pressure to the large end of the piston beforeshoulder |36 laps land |26. This prevents completely sealing off thepump.

Operation of the deviceof the invention isA as follows:

With the parts of the device in the positions shown in Figure 2, uidfrom the reservoir is pumped through port 86 between the right end ofsleeve |28 and section 42, through opening |24, through the interior ofthe sleeve, past opening |22, then between the left end of sleeve |20and section 42, and thence into port 88 Vwhich is connected to thesteering valve. Since the steering valve is of the open center type, uidleaving the working port 88 passes freely through the steering valveback to reservoir when steering is not required.

To perform a brake application, some or all of the fluid normally usedfor steering is diverted therefrom to be used for actuating the brakes.To divert the fluid, as aforementioned, the operator of the vehicle, notshown, depresses pedal Il! which moves sleeve |20 relative to the pistonvalve |30. This movement of the sleeve to the right uncovers the slots|38 of the piston valve to admit iluid under pressure to the large head68 of piston 66 to cause movement of the piston 66 to the right.Movement of the piston to the right permits the head 40, which iscarried by the piston valve, to follow to the right with the pistonsince the piston valve is spring-loaded by the spring |46. It will benoted also that the iiuid under pressure acting on the large head 68acts on the right end of sleeve |20 tending to urge it to the leftagainst the force applied to the pedal by the operator. Therefore, thegreater the force acting on the piston tending to move the piston to theright, the greater is the force acting on the right end of the sleeve|20 tending to counteract the applied force on the pedal. With thisarrangement we have not only position control, but feel Since the systembeyond the small head 10 of piston 66 is a closed'system, movement ofthe piston to the right puts the fluid in the brakes under pressure. Inthe instant application, the unit pressure produced on the right end ofpiston 66 is greater than the unit pressure actingon the left end of thepiston urging it to the right. This is commonly known as a boosterarrangement and is used where ahigher pressure is needed for operatingthe` brakes than is available at the pump.

During steering, the fluid in the system between the pump and thesteering valve is put under pressure. Therefore, if a brake applicationis made at this time, there will be immediately available for initialbraking, fluid under pressure, to admit past slots |36 vto act on thelarge end of piston 66. However, as aforementioned, when steering is nottaking place there is only enough pressure on the fluid to overcome theresistance of the system offered to the ilow of fluid. Hence in making abrake application when steering is not taking place, movement of sleevemust be to the right far enough to provide a substantial restriction tothe flow past shoulder |36 so as to quickly build up a pressureV in port8l to initiate the brake action. f

Upon release of the pedal, the spring |46 returns the piston and sleeveto their normal rela-` tive positions, and the fluid under pressureacting on the large head 68 and on the right end of sleeve |20 tends toreturn the sleeve to its normal position at the left so that element |56engages land 52. This unseats valve head which allows the fluid underpressure which was acting on the large head 68 to be dissipated throughopening l I3, radial passage |08 and reservoir port 84 to reservoir. Therelease of fluid under pressure acting on the large head 68 of thepiston permits the piston to return to the left under the influence ofspring 92, and the pressure built up in the brakes. When the piston hasnearly reached its extreme leftward position, valve pin |02 engages theflange 14 to unseat ball valve 96 to open that part of the system fromvalve |8 to the brakes, to reservoir. Connecting this portion of thesystem to 'reservoir after each brake application, as aforementioned,insures a full volume of oil at all times. l

Although the invention has been described in connection with certainspecific embodiments, the principles are susceptible of numerous otherapplications that will readily occur to those skilled in the art. YTheinvention is, therefore, to be limited only as indicated by the scope ofthe appended claims. i

Having thus described the various features of Lthe invention, what Iclaim as new and desire to secure by Letters Patent is:

I claim:

1. A valve for use in a hydraulic system `comprising a body, a bore inthe body, a piston in the bore having a normal relative positiontherein, a first Working port opening into the bore, a reservoir portopening into the bore, a spring l biasing the piston to its normalrelative position in the bore, said piston responsive to fluid underpressure acting on one end thereof to move the same against the springto put fluid under pressure in the first working port, said piston andbore together constituted to provide a chamber which is in constantcommunication with said reservoir port only, a passage in the pistonconnecting the chamber to said one end of the piston, a valve seat inthe passage, a, pumping port opening into the bore, a second workingport opening into the bore and axially spaced apart from the pumpingport opening, operator operated mea in the bore to control communicationbetween the pumping port and the second working port and said one end ofthe piston, said means including a sleeve, a piston valve in the sleeve,a land in the bore intermediate the pumping port and vsecond workingport to cooperate with the' exterior of the sleeve to provide a barrierto the passage of fluid between the pumping port and second working portexteriorly of the sleeve. and-.a valve head carried by the piston valveto ,normallyengage the valve seat to obturate the passage, sai-d sleevehaving openings therein to connect the pump- `ing port tothe secondworking port and to said the piston valve restricts communicationbetween I the pumping portl and the second working port and establishescommunication between the pumping port and said one end of the piston tosubject that end of the piston to fluid under pressure to move thepiston toward one end of the` bore to -put fluid in the first workingportunder.

pressure. A

2. A valve for use in a hydraulic system comprising a body, a bore inthe body, a piston in the bore having a normal relative positiontherein, a first working port opening into the bore, a reservoir portopening into the bore, a

spring biasing the piston to its normal. relative position in the bore,said piston responsive to iiuid under pressure acting on one end thereofto move the same against the spring to put fluid under pressure in thefirst working port, said piston andbore together constituted to providea chamber winch is in constant communication with said reservoir portonly, a, passage in the piston connecting the chamber to said one end ofthe piston, a valve seat in the passage, a pumping port opening into thebore, a second Working port opening into the bore, operator operatedmeans in the bore to control communication between the pumping port andthe second working port and said one end of the piston, said meansincluding a sleeve, a piston valve in the sleeve, a land in the boreintermediate the pumping port and second working port to cooperate withthe exterior of the sleeve to provide a barrier to the passage of nuidbetween the pumping port and second working port exteriorly of thesleeve, and

a valve head carried by the piston valve to normally engage the valveseat to obturate the passage, said valve seat constructed and arrangedto move out of engagement with the valve head in response to fluid underpressure above a predetermined value acting on said one end of thepiston to release said pressure to reservoir, said sleeve havingopenings therein `to connect the pumping port to the second working portand to said one end of the piston through the interior of the sleeve,said piston valve constructed and arranged to cooperate with theopenings in the sleeve to normally establish communication between thepumping port and second working port and cut off communication betweenthe pumping port and said one end of the piston, said sleeve and pistonvalve movable together in the bore and also relatively movable wherebymo'ement of the sleeve in the bore relative lto the piston valverestricts communication between the pumping port and the second workingports and establishes communication between the pumping port and saidone end of the piston to subject that end of the piston to fluid underpressure to move the piston toward one end of the bore to put fluid inthe first working port under pressure.

3. A valve for controlling the flow of fluid comprising a body, a borein the body, a first working port opening into one end of the bore, areservoir portopening into the bore, a piston slideable in one end ofthe bore to put fluid in the first working port under pressure when thepiston is moved toward said one end of the bore, a spring disposed inone end of the bore to urge the piston toward the other end thereof,said piston movable to said one end of the bore by fluid under pressureacting on one end of the piston, said piston and bore togetherconstituted to provide a chamber which is in constant communication withsaid reservoir port, a passage in the piston to provide communicationbetween the chamber and said one end of the piston, a valve seat in thepassage, a pumping port opening into the bore, a second working portopening into the bore, and means disposed in the bore to control the owof fluid from the pumping port to the second working port and to saidone end of the piston, said means including means to normally establishcommunication between the pumping port and the second working port andto cut off communication between the pumping port and said one end ofthe piston and having a valve head constructed and arranged to seat onthe valve seat to normally close the passage, said first and secondmentioned means movable in the bore as a unit and also relativelymovable to restrict communication between the pumping port and thesecond working port and establish communication between the pumping portand said one end of the piston to subject that end of the piston toiiuid under pressure to thereby move the piston to put fluid in thefirst working port under pressure.

4. In a valve of the class described in claim 3, wherein means isprovided to establish communication between the first working port andthe reservoir port when the piston is moved to a predetermined positionin the bore under the influence of the spring to thereby replenish thefluid in the first working port after each cycle of operation.

5. A valve Vfor controlling the flow of fluid comprising a body, a borein the body, a first Working port opening into one end of the bore, areservoir port opening into the bore, a piston slldeable in one end ofthe bore to put fluid in the rst working port under pressure when thepiston is moved toward said one end of the bore, a spring disposed inone end of the bore to urge the piston toward the other end thereof,said piston movable to said one end of the bore by fluid under pressureacting on one end of the piston, said piston and bore togetherconstituted to provide a chamber which is in constant communication withsaid reservoir port only, a passage in the piston to providecommunication between the chamber and said one end of the piston, avalve seat in the passage, a pumping port opening into the bore, asecond working port opening into the bore, and means disposed in thebore to control the flow of fluid from the pumping port to the secondworking port and to said one end of the piston, said means includingmeans to normally establish communication between the pumping port andthe second working port and to cut off communication between thenumpmgport and said one end of the piston and having a valve headconstructed and arranged to seat on the valve seat to normally close thepassage, said valve seat constructed and arranged to move away from thevalve head to release fluid under pressure acting on said one end oi thepiston when the pressure exceeds a predetermined value, said first andsecond mentioned means movable in the bore as a unit and also relativelymovable to restrict communication between the pumping port and thesecond working port and establish communication between the pumping portand said one end of the piston to subject the same to fluid underpressure to thereby move the piston to put duid in the first workingport under pressure.

6. A valve for controlling the flow of fluid comprising a body, a borein the body, a first working port opening into one end of the bore, areservoir port opening into the bore, a piston slideable'in one end ofthe bore to put fluid in the first working port under pressure when thepiston is moved toward said one end of the bore, a. spring disposed inone end of the bore to "urge the piston toward the other end thereof,said piston movable to said one end of the bore by fluid under pressureacting on one end of the piston, said piston and bore togetherconstituted to provide a chamber which is in constant communication withsaid reservoir port only, a passage in the piston to providecommunication between the chamber and said one end of the piston, avalve seat in the passage, a pumping port opening into the bore, asecond working port opening into the bore, and means disposed in thebore to control the flow of fluid from the pumping port to the secondworking port and to said one end of the piston, said means includingmeans to normally establish communication between the pumping port andthe second `working port and to cut off communication between thepumping port and said one end of the piston and having a valve headconstructed and arranged to seat on the valve seat to normally close thepassage, said first and second mentioned means movable in the bore as aunit and also relatively movable to restrict communication between thepumping port and the second working port and establish communicationbetween the pumping port and said one end of theA piston to subject thatend of the piston to fluid under pressure to thereby move the piston toput uid in the first working port under pressure, said rst mentionedmeans is so arranged within the bore that should fluid under pressurenot be available, said first mentioned means can be manually moved in a.direction to engage said one end of the piston to move the same towardsaid one end of the bore to put fluid in the first working port underpressure.

'7. A valve for use in a fluid system comprising a body, a bore in thebody, a piston located in one end of the bore and having a normalrelative position therein, a first working port in said one end of thebore, a spring urging the piston toward its normal relative position,said piston movable out of its normal relative position against thespring in response to fluid under pressure acting on one end of thepiston to thereby put fluid in the first working port under pressure, areservoir port opening into the bore, a pumping port opening into thebore, a second working port opening into the bore, means located in thebore to control the flow of fluid between the pumping port and thesecond working port and said one end o1' the piston, and meansassociated with the piston including a valve normally closed and.operatively connected to said iirst mentioned means to control therelease of nuid under pressure acting on said one end of the piston tothe reservoir port, said rst mentioned means comprising nested sleeveand piston valve disposed within the bore for limited axial movement asa unit in either direction and relatively slidable with respect to eachother for a limited axial distance in either direction from a normalrelative position. said sleeve and piston valve together constituted sothat when they are'in their normal relative position communication isestablished between the pumping port and the second working port and cutoiibetween the pumping port and said one end of the piston and. whensaid sleeve and piston valve are moved relative to each othercommunication is restricted between the pumping port and the secondworking port and established between the pumping port and said one endof the piston to move the same against the spring to put fluid in thefirst working port under pressure, said iirst mentioned means responsiveto the fluid under pressure acting on said one end of the piston to opensaid normally closed valve to effect release of the fluid to thereservoir port.

8. A valve for controlling the flow of fluid comprising a body having abore therein, a piston in the bore dividing the same into opposedchambers, a iirst port in said body opening into one end of said bore, asecond port in said body normally uncomrnunicable with the ends of saidbore, valve means carried by said piston for establishing communicationbetween said second port and the other end of said bore, third andfourth ports opening into the other end of said bore, axially shiftablemeans arranged in the other end of said bore so that said third port isnormally in communication with said fourth port, said piston movable tosaid one end of the bore under the influence of fluid under pressureacting on one end thereof to thereby put fluid in said iirst port underpressure, a spring in said one end of the bore arranged to urge saidpiston toward the other end thereof, said axially shiftable meanscomprising a valvemechanism mechanically intercOnnected'with said valvemeans 5 and operative to restrict communication between said third andfourth ports and establish communication between said third port andsaid one V-end of the piston, to thereby move the same toward one end ofsaid bore.

9. A valve for controlling the flow of uid comprising a body having abore therein, a piston in the bore, a first port in said body openinginto one end of said bore, a. second port in said body normallyuncommunicable with the ends of l5 said bore, valve means carried bysaid piston for establishing communication between said second port andthe other end of said bore, third and fourth ports opening into theother end of sa`d bore, fluid cont-rol means arranged in the 20 otherend of said bore so that said third port is normally in communicationwith said fourth port, said piston movable to said one end of the boreunder the iniiuence of fluid under pressure acting on one end thereof tothereby put uid in 25 said rst port under pressure, and means in saidone end of the bore for urg'ng said piston toward the other end thereof,said control means comprising a valve mechanism mechanicallyinterconnected with said valve means and operative 30 to restrictcommunication between said third and fourth ports and establishcommunication between said third port and said one end of the piston.

STANLEY I. MACDUFF.

. REFERENCES cr'rEn The following references are of record in the illeof this patent:

